package function.builtin

import environment.RuntimeEnvironment
import error.ErrorManager
import function.ArgumentValidator.BadArgumentTypeException
import function.ArgumentValidator.TooFewArgumentsException
import function.ArgumentValidator.TooManyArgumentsException
import org.assertj.core.api.Assertions.assertThat
import org.junit.jupiter.api.Assertions.assertThrows
import org.junit.jupiter.api.Test
import testutil.LispTestInstance
import testutil.SymbolAndFunctionCleaner
import testutil.TestUtilities.evaluateString
import testutil.TypeAssertions.assertNil
import testutil.TypeAssertions.assertT
import java.io.ByteArrayOutputStream
import java.io.PrintStream

@LispTestInstance
class LoadTest : SymbolAndFunctionCleaner() {

    private var outputStream = ByteArrayOutputStream()
    private var errorOutputStream = ByteArrayOutputStream()

    private fun assertWarningMessagePrinted() {
        assertThat(outputStream.toByteArray()).isNotEmpty()
        assertThat(errorOutputStream.toByteArray()).isEmpty()
    }

    private fun assertErrorMessagePrinted() {
        assertThat(errorOutputStream.toByteArray()).isNotEmpty()
        assertThat(outputStream.toByteArray()).isEmpty()
    }

    private fun assertNothingPrinted() {
        assertThat(errorOutputStream.toByteArray()).isEmpty()
        assertThat(outputStream.toByteArray()).isEmpty()
    }

    override fun additionalSetUp() {
        outputStream.reset()
        errorOutputStream.reset()

        RuntimeEnvironment.reset()
        RuntimeEnvironment.output = PrintStream(outputStream)
        RuntimeEnvironment.errorOutput = PrintStream(errorOutputStream)
        RuntimeEnvironment.errorManager = ErrorManager()
        RuntimeEnvironment.path = ""
        RuntimeEnvironment.warningOutputDecorator = { it }
        RuntimeEnvironment.errorOutputDecorator = { it }
    }

    override fun additionalTearDown() {
        RuntimeEnvironment.reset()
    }

    @Test
    fun loadEmptyFileName_ReturnsNilAndPrintsWarning() {
        val input = "(load \"\")"

        assertNil(evaluateString(input))
        assertWarningMessagePrinted()
    }

    @Test
    fun loadGoodFile_ReturnsTAndPrintsNothing() {
        val file = LoadTest::class.java.getResource("load-good.lisp").file
        val input = "(load \"$file\")"

        assertT(evaluateString(input))
        assertNothingPrinted()
    }

    @Test
    fun loadBadFile_ReturnsNilAndPrintsError() {
        val file = LoadTest::class.java.getResource("load-bad.lisp").file
        val input = "(load \"$file\")"

        assertNil(evaluateString(input))
        assertErrorMessagePrinted()
    }

    @Test
    fun loadNonExistentFile_ReturnsNilAndPrintsWarning() {
        val input = "(load \"doesNotExist.lisp\")"

        assertNil(evaluateString(input))
        assertWarningMessagePrinted()
    }

    @Test
    fun nestedLoadsInTheSameDirectory() {
        val file = LoadTest::class.java.getResource("nested/nested.lisp").file
        val input = "(load \"$file\")"

        assertT(evaluateString(input))
        assertNothingPrinted()
    }

    @Test
    fun nestedLoadsInDifferentDirectories() {
        val file = LoadTest::class.java.getResource("nested/one/load-one.lisp").file
        val input = "(load \"$file\")"

        assertT(evaluateString(input))
        assertNothingPrinted()
    }

    @Test
    fun loadWithBadArgumentType() {
        assertThrows(BadArgumentTypeException::class.java) {
            evaluateString("(load '1)")
        }
    }

    @Test
    fun loadWithTooManyArguments() {
        assertThrows(TooManyArgumentsException::class.java) {
            evaluateString("(load \"1\" \"2\")")
        }
    }

    @Test
    fun loadWithTooFewArguments() {
        assertThrows(TooFewArgumentsException::class.java) {
            evaluateString("(load)")
        }
    }

    @Test
    fun loadUsesRuntimePath() {
        RuntimeEnvironment.path = LoadTest::class.java.getResource("nested/one/").path
        val input = "(load \"load-one.lisp\")"

        assertT(evaluateString(input))
        assertNothingPrinted()
    }
}